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Consolini, Giuseppe
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Consolini, Giuseppe
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Consolini, G.
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103 results
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- PublicationOpen AccessThe Complex Nature of Magnetic Element Transport in the Quiet Sun: The Multiscaling CharacterIn recent studies the dynamic properties of small-scale magnetic fields (magnetic elements [MEs]) in the quiet Sun were used to investigate peculiar features of turbulent convection and get insights on the characteristic spatial and temporal scales of evolution of magnetic fields, from granular to supergranular. The aim of this work is to extend previous studies and show that the displacement of MEs is compatible with a multiscaling behavior consistent with a Lévy motion. We tracked over 120,000 MEs in an unprecedented and uninterrupted set of high-resolution magnetograms acquired by the Hinode mission and targeted at quiet-Sun regions in the disk center, and we applied the multifractal diffusion entropy analysis to investigate the multiscaling character of ME transport in the quiet Sun. We found that the displacement of MEs in the quiet Sun exhibits a complex multiscaling behavior that cannot be described by a unique scaling law, as scaling exponents change with the scale considered. This result adds important physical constraints on turbulent convection and diffusion of MEs in the quiet Sun that future models need to account for.
192 7 - PublicationOpen AccessDissipation of field-aligned currents in the topside ionosphere(2022)
; ; ; ; ; ; ; ; ;; ; ; ; Field‐aligned currents (FACs) are electric currents parallel to the geomagnetic field and connecting the Earth’s magnetosphere to the high‐latitude ionosphere. Part of the energy injected into the ionosphere by FACs is converted into kinetic energy of the surrounding plasma. Such a current dissipation is poorly investigated, mainly due to the high electrical conductivity and the small electric field strength expected in direction parallel to the geomagnetic field. However, previous results in literature have shown that parallel electric field is not null (and may be locally not negligible), and that parallel electrical conductivity is high but finite. Thus, dissipation of FACs may occur. In this work, for the first time, we show maps of power density dissipation features associated with FACs in the topside ionosphere of the Northern hemisphere. To this aim, we use a 6‐year time series of data at one second cadence acquired by the European Space Agency’s “Swarm A” satellite flying at an altitude of about 460 km. In particular, we use data from the Langmuir probe together with the FAC product provided by the Swarm team. The results obtained point out that dissipation of FACs, even if small when compared to that associated with horizontal currents flowing about 350 km lower, is not null and shows evident features co‐located with electron temperature at the same altitude. In particular, power density dissipation features are enhanced mainly in the ionospheric regions where intense energy injection from the magnetosphere occurs. In addition, these features depend on geomagnetic activity, which quantifies the response of the Earth’s environment to energetic forcing from magnetized plasma of solar origin.565 10 - PublicationOpen AccessParallel electrical conductivity in the topside ionosphere derived from Swarm measurements(2021)
; ; ; ; ; ; ; ; ;; ; ; ; Our knowledge of the physical properties of the topside ionosphere is still incomplete. A key point still not fully understood is how field aligned currents are generated, evolve and dissipate in the ionosphere. Answering to this question is fundamental for a better understanding of the mechanisms regulating the coupling between magnetosphere and ionosphere and to shed light on the physical processes inherent to space weather events occurring in the Earth’s ionosphere. In this framework a relevant role is played by the ionospheric conductivity. The purpose of this study is to analyze the main properties of the electrical conductivity parallel to the geomagnetic field from a climatological point of view. The statistical study of the electrical conductivity is proposed using four years of in‐situ electron density and temperature measurements at 1 Hz acquired by the ESA’s Swarm A satellite. Variations due to seasonal effects are also investigated. Finally, starting from observations and comparing our results with those obtained using IRI model, we give a first estimation of the conductivity mainly due to particle precipitation.778 80 - PublicationRestrictedFluid motions in the Earth’s core inferred from time spectral features of the geomagnetic field(2002)
; ; ; ;Consolini, G.; Istituto di Fisica dello Spazio Interplanetario, CNR, I-00133 Roma, Italy ;De Michelis, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Meloni, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;; The aim of this work is to investigate the time spectral features of the main geomagnetic field fluctuations as measured on the Earth’s surface in connection with a nontraditional turbulent dynamics of the fluid motions in the outer layers of the Earth’s liquid core. The average geomagnetic field spectrum is found to be a power law, characterized by a spectral exponent α≈−11/3, on time scales longer than 5 yr. We discuss the spectral exponent in connection with an intense magnetic field in the Earth’s core and with a vortex coalescence process in a regime of drift-wave turbulence.440 32 - PublicationOpen AccessTesting the Steady-State Fluctuation Relation in the Solar Photospheric Convection(2020-06-28)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; The turbulent thermal convection on the Sun is an example of an irreversible non-equilibrium phenomenon in a quasi-steady state characterized by a continuous entropy production rate. Here, the statistical features of a proxy of the local entropy production rate, in solar quiet regions at different timescales, are investigated and compared with the symmetry conjecture of the steady-state fluctuation theorem by Gallavotti and Cohen. Our results show that solar turbulent convection satisfies the symmetries predicted by the fluctuation relation of the Gallavotti and Cohen theorem at a local level.131 12 - PublicationOpen AccessTime intermittency and spectral features of the geomagnetic field(2004)
; ; ;De Michelis, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Consolini, G.; Istituto di Fisica dello Spazio Interplanetario - CNR, Roma, Italy; In the field of geomagnetism a number of studies have been devoted to the investigation of turbulence and intermittency in the outer core fluid motions. Here, in order to obtain information on such phenomena we study the time spectral and self-similarity features of the main geomagnetic field fluctuations as measured on the Earth’s surface. The existence of a power law spectrum, characterised by an exponent a˜-11/3, and an anomalous scaling of q-th order structure functions on time scales longer than 5 years, suggests the occurrence of intermittent turbulence rather than classical Kolmogorov turbulence in the fluid core motions. These results are briefly discussed in connection with the existence of a strong magnetic field and drift-wave turbulence.189 189 - PublicationOpen AccessObservations of high-latitude geomagnetic field fluctuations during St. Patrick’s Day storm: Swarm and SuperDARN measurements(2016-06-21)
; ; ; ; ; ; ; The aim of this work is to study the properties of the magnetic field’s fluctuations produced by ionospheric and magnetospheric electric currents during the St. Patrick’s Day geomagnetic storm (17 March 2015). We analyse the scaling features of the external contribution to the horizontal geomagnetic field recorded simultaneously by thethree satellites of the Swarm constellation during a period of 13 days (13–25 March 2015). We examine the different latitudinal structure of the geomagnetic field fluctuations and analyse the dynamical changes in the magnetic field scaling features during the development of the geomagnetic storm. Analysis reveals consistent patterns in the scaling properties of magnetic fluctuations and striking changes between the situation before the storm, during the main phase and recovery phase. We discuss these dynamical changes in relation to those of the overall ionospheric polar convection and potential structures as reconstructed using SuperDARN data. Our findings suggest that distinct turbulent regimes characterised the mesoscale magnetic field’s fluctuations and that some factors, which are known to influence large-scale fluctuations, have also an influence on mesoscale fluctuations. The obtained results are an example of the capability of geomagnetic field fluctuations data to provide new insights about ionospheric dynamics and ionosphere–magnetosphere coupling. At the same time, these results could open doors for development of new applications where the dynamical changes in the scaling features of the magnetic fluctuations are used as local indicators of magnetospheric conditions.167 8 - PublicationRestrictedA THERMODYNAMIC APPROACH TO THE MAGNETOSPHERIC COMPLEXITY: THE ROLE OF FLUCTUATIONS(2006)
; ; ; ;Istituto di Fisica Spazio Interplanetario, INAF, 00133 Rome, Italy ;Istituto di Nazionale di Geofisica e Vulcanologia, 00143 Rome, Italy ;Royal Observatory of Belgium, 1180 Brussels, Belgium ;Consolini, G.; 1Istituto di Fisica Spazio Interplanetario, INAF ;De Michelis, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Kretzschmar, M.; Royal Observatory of Belgium, 1180 Brussels, Belgium ;; Recent studies evidenced that the magnetotail dynamics looks like the one of an avalanching system. This fact has been related with a near criticality dynamics and modelled by singular diffusion and transport equations. Here, we discuss some features of the Earth’s magnetotail dynamics using a thermodynamic approach. In detailwediscuss the role played by fluctuations in singular diffusion and relaxation processes from a non-equilibrium thermodynamics point of view. Moreover, the emergence of non-Gaussian statistics is discussed in the framework of the thermodynamics of composite systems.158 24 - PublicationRestrictedAn information theory approach to the storm‐substorm relationship(2011-08-27)
; ; ; ; ;De Michelis, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Consolini, G.; Istituto Nazionale di Astrofisica–Istituto di Fisica dello Spazio Interplanetario, Rome, Italy ;Materassi, M.; Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, Sesto Fiorentino, Italy ;Tozzi, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; ;; One of the most interesting aspects of the global magnetospheric response to solar wind changes is the relationship between storms and substorms. Here we present new results on the relationship between these two different classes of magnetospheric phenomena by approaching the problem on the side of information theory. Using the Auroral Electrojet AL and SYM‐H indices as representative proxies of magnetic substorms and storms, we investigate the transfer of information by means of transfer entropy analysis (Schreiber, 2000). The obtained results seem, on average, to indicate the presence of a net transfer of information from AL to SYM‐H on time scales shorter than 10 h. On the basis of this result, geomagnetic substorms may act as a driver for the occurrence of geomagnetic storms. However, carrying out a more careful analysis which takes into account the global geomagnetic daily activity, we suggest that the direction of information flow between substorms and storms depends on the global activity level. Indeed, if it is true that a sequence of magnetospheric substorms may drive a moderate storm, it is also true that very large storms may dominate and drive the occurrence of magnetospheric substorms.453 43 - PublicationOpen AccessIonospheric Turbulence: A Challenge for GPS Loss of Lock Understanding(2022-07)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Ionospheric irregularities may affect electromagnetic signals propagating through the ionosphere and consequently contribute to the malfunctioning of the Global Navigation Satellite Systems hindering their accuracy and reliability. In this study, we use data recorded on board two of the three satellites of the Swarm constellation (namely, Swarm A and Swarm B) from July 15th, 2014 to December 31st, 2021 to assess the possible dependence of the Global Positioning System (GPS) signals loss of lock on the presence of a specific kind of ionospheric irregularities. To accomplish this task we study the scaling features of the electron density fluctuations through the structure function analysis simultaneously to the occurrence of loss of lock events through measurements recorded by the Langmuir probes and the precise orbit determination antennas on board Swarm A and Swarm B satellites. We find that the plasma density irregularities in a turbulent state characterized by intermittent structures and extremely high values of the Rate Of change of electron Density Index can lead to GPS loss of lock events. This is always true at mid- and high-latitudes, especially inside the auroral oval. In the equatorial belt, this happens in at least 75% of identified GPS loss of lock events that basically coincide with the occurrence of plasma bubbles.701 56